1. Field of the Invention
The present invention relates to a display control method and a display control apparatus adaptable to electronic equipment which has a display unit and which can be operated by a battery, for example, a portable information processing apparatus including a battery which can electrically be charged and having a display, such as a flat panel display, which can be operated by the battery.
2. Description of the Related Art
A portable information processing apparatus having a display unit and enabled to be operated by a battery has variously been contrived in order to prevent wasteful electric power consumption when operated by the battery.
As one of methods of saving electric power, a so-called automatic display-turn-off function can be employed with which the operation of a mouse or a keyboard is monitored by a timer, and if the mouse and the keyboard is not operated within a predetermined time period, then the display operation is interrupted so as to save electric power.
An automatic display-turn-off function of the foregoing type of the conventional personal computer has been arranged such that the automatic display interruption time, which has been once set, is not changed (a fixed time is set) until the time is again set.
With a small-size electronic equipment, such as a personal computer, if the automatic interruption time is shortened in a case where the electronic equipment is operated by the battery, the usage of the battery can be reduced. On the other hand, the handling facility deteriorates. If the automatic interruption time is elongated, the handling facility is improved. However, the usage of the battery is enlarged.
As described above, since the automatic display-interruption-time has been fixed, the life of the battery and the handling facility for the user cannot easily be adjusted. Moreover, the contents of an intended process and the characteristics of the operation of the user result in different relationship.
A flat panel display of a type, having a backlight, a sidelight or the like, is enabled to save electricity by darkening the brightness of the backlight.
Also control of the display of the foregoing type has been performed such that the brightness, which has been set, is not changed (fixed brightness is set) until it is set again.
Although the usage of the battery of a small-size electronic equipment, such as a personal computer, can be reduced if the brightness is darkened (lowered) in a state where it is operated by a battery, the display cannot easily visually be observed. If the brightness is raised, the display can easily be recognized. However, the usage of the battery is enlarged.
In a case where the brightness of the display is fixed as described above, the life of the battery and easy recognition of the display cannot easily be adjusted. Moreover, the environment of use of the equipment, the environmental illumination, contamination of the surface of the display and lowering of the brightness as the time elapses cause different results to take place.
As a conventional method of saving electricity which is consumed by a display, a display control method is known which has the steps of monitoring the mouse and the keyboard; and interrupting the operation of the display if the mouse or the display is not operated within the time, which has been set previously, so that electricity is saved.
However, the above-mentioned conventional display control involves waste in the electric power consumption because the display is in the display operation state until the set time elapses even if the display is not watched.
If the mouse or the keyboard is not operated during the period in which the display is watched, the display operation is interrupted during watching. Therefore, the operation facility is unsatisfactory.
As a conventional method of saving electricity of a (flat panel type) display, a display control means is known in which the brightness of the backlight is darkened after a set time has elapsed so that electricity is saved.
However, the foregoing conventional display control involves waste in the electric power consumption because the display is in the display state until the set time elapses even if the display is not watched.
As described above, all of the conventional display control means for saving electricity involve waste of electric power consumption, and a satisfactory effect for saving electricity cannot be obtained when the electronic equipment is operated by a battery.